Hi gang,

I've added another truck to the fleet, a 1995 C1500 Suburban. I've been fixing it up over the summer and driving it back and forth to Eastern Washington. I've recently run into a problem that has me stumped and I'm wondering if any of you have any experience with it.

I replaced the steering gearbox in late July because it was having problems with wandering on center and the gearbox was pretty worn out. The replacement box I got from O'Reilly's had more issues so I took it to my local Firestone to have them deal with it since I didn't have time and was heading out of town. They replaced the steering gearbox and I took it out on the highway and discovered that when I hold the steering wheel at about thirty degrees to the right of center the truck will jerk back and forth as though I were turning the wheel back and forth quickly.

What causes that behavior? Is it a hydraulic problem with the steering gear? Mechanical? I'm going to take the 'Burb back to them and let them diagnose the problem but, in the mean time, I'd like to get your opinion of what's going on.